Electromechanical interlock for elevator doors



Sept. 24, 1946. PENN 2,408,054

ELECTROMECHANICAL INTERLOCK FOR ELEVATOR DOORS Filed May 13, 1945 2Sheets-Sheet l F 99 1 I nzrentor' [272023 lkFenn Sept. 24, 1946. w FENNELECTROMECHANICAL INTERLOCK FOR ELEVATOR DOORS I 2 Sheets-Sheet 2 FiledMay 13, 1945 Patented Sept. 24, 1946 ELECTROMECHANICAL INTERLOCK FORELEVATOR DOORS Emory W. Fenn, Chicago, Ill., assignor to FirecraftCorporation, a corporation of Illinois Application May 13, 1943, SerialNo. 486,765

16 Claims.

This invention relates to electro-mechanical interlocks for hoistwaydoors for freight elevators and the like.

It is an object of my invention to provide an electro-mechanicalinterlock which is substantially tamper-proof.

It is a further object of my invention to provide in connection withbiparting door panels an interlock which cannot be rendered inoperativeunless the door suspension mechanism also is rendered inoperative.

Another object is to provide a novel, simple, compactelectro-niechanical interlock mechanism.

An additional object is to provide an interlock requiring the doors atall floors to be latched before the car can be started; positivelypreventing opening movement of all latches while the car is in motion oris not at any floor; and positively preventing opening movement of alllatches eX- cept that associated with the floor at which the car is atrest.

It is also an object of my invention to provide in an automatic orpush-button controlled elevator an electromechanical interlock havingthe features noted above, and, in addition, whereby the car-controllingcircuit is locked open when the car comes to rest at the selected floorand until a button is pushed, and may then be closed only if all doorsare latched.

Further objects and advantages of the invention will appear as thedescription proceeds.

My invention will be better understood upon Fig. 3 is an enlargedfragmentary elevational view taken as indicated by the line 3-3 in Fig.2

and showing details of an interlock mechanism for a push-buttoncontrolled type elevator in accordance with one form of my invention.

Fig. 4 is a fragmentary elevational View take as indicated by the line4-4 in Fig. 3.-

Fig. 5 is a view similar to Fig. 3 but with the interlock switchautomatically opened.

Fig. 6 is a fragmentary elevational view taken as indicated by the lineE-6 in Fig. 5.

Fig. 7 is similar to Fig. 3 but shows the door latch in open position,the doors controlled by such latch being separated.

Figs. 8 and 9 are fragmentary plan sectional views taken as indicated bythe lines 83 and =l-d, respectively, in Fig. '7.

Fig. 10 is a fragmentary elevational view similar to Fig. 7 but with theautomatic switch-opening means omitted, asin the case of a non-automaticelevator.

Referring now more particularly to the drawings, I have shown anelevator well or shaft 20 (Fig. 9) defined by a wall 22 having a dooropening of which the sill is shown at 2 5, a biparting door 26comprising upper and lower door panels or sections 28 and iii, and a car32. Attached to the wall 22 at each side is a vertical guide member 34to which are attached upper and lower vertical guide members 36 and 31providing guide- Ways 38 in which run guide angles 39 carried at thevertical edges of the door panels and forked guide shoes 4!! attached asat 42 near the top and bottom of each angle 39. Th forks (Fig. 9)receive and move vertically relative to the respective guide members 36and 31, shown in other figures.

Secured to the lower door section 38 as at 48 is an arm 50 extendingbeyond said section and carrying adjacent its free end a bracket 52through which the lower threaded end 54 of an anchoring member 56extends, said end 54 receiving a nut 53 by means of which said anchoringmember may be retained and adjusted in relation to the bracket member52. Secured as at 69 to the upper part 62 of the anchoring member 56 isa chain rod 64 whose upper end is attached as at E6 to a flexiblesuspension member such as a cable chain 68 passing about a wheel orsheave it suitably mounted as at 12 in fixed relation to the guidemembers 3 5 and 36. The chain depends from the other side of the sheaveand is secured as at M to the lower part of the upper door section 28.The adjustment of the doors for proper operation ofthe interlock may bemodified by adjustment of the nut 58. Only the flexible portion '58 isin contact with the sheave 10 for all positions of the door sections 28and 30.

When the door is closed, the sections 28 and 30 are disposed adjacenteach other substantially as shown in Fig. 1, rubber or like bumpers 16carried by either section being provided at suitable intervals betweenthe bottom flange E8 of the upper section and the top flange 8B of thelower door section 30.

The doors may be latched together by any suitable mechanism, of which anillustrative form is shown in Fig. 1. Here, preferably in a suitableframe 82 secured to the inner face of the upper door section 23, thereis pivotally attached as at 84 a bell crank lever 85 having a handle 88(on the outside as well as the inside in the case of a push-buttonelevator) conveniently accessible to the operator on a car at rest atthe associated floor level, and a second arm 98 extending in a generallyvertical direction where it is resiliently maintained preferably as by acompression spring 3 92 disposed between an adjustable abutment 94 and alug 96 formed on the lever 86. The arm 99 is formed at its lower endwith a hook or catch Ilsadapted to extend through an opening I in thetop 85 of the lower section 39 and adapted also, when projected throughsaid opening I00,

to be moved bythe spring 92 under and beyond th wall of the opening I00as shown in Fig. 1, 7

a block I06 suitably attached as to the angle 39- of the door section28. The latch bar I04 is adapted to extend beyond the angle 39 and hasan offset lug IIlB adapted to cooperate with interlock mechanism in ahousing I I!) having a removable cover H2 and mounted as by suitablebolts, oneof which is shown at II4, on the stationary guide members 34and 36.

In accordance with my invention, there is provided in association witheach landing a switch lever arm IIB pivoted in the housing at I25. Alocking bolt I22 may be connected to the lever I I8'inany suitablemanner, and for example may have a slotted upstanding boss I24 pivotallyconnected as at I26 to a yoke or fork I28 on the lever I I8. ifihehousing I II} preferably has a guide opening I30 for sliding movement ofa projection I32 extending from the bolt I22. The bolt I22 at the endI34 thereof opposite the projection I32 is adapted to slidingly bear onthe bearing surface I36 of the housing III], the only other slidingcontact between the bolt and the housing occurring between the bottom ofthe opening I32 and the bottom of the bolt extension I32, wherebyfriction is at a minimum. Said end I34 of the bolt I22 has a notch I33open and flared at the top as at I411 to facilitate entry of the lug I08on the latch bar I04 into the notch.

The lever H8 is provided with an insulating plate or block I42 fromwhich projects a pin I44 about which a coil spring I46 is disposed, saidpin having a non-circular portion passingthrough a metallic bridgemember I48 and formed at its free end to retain the bridge inassociation therewith, the spring I46 constantly urging the bridge I48toward the free end of the pin. The'bridge Iflrnay be'provided withelectric contact points I59 and I52, adapted to engage respectivelystationary contacts I54 and I55 mounted on an insulating block I58 fixedto the housing I III. The contacts I 3 and I56 are in an electriccircuit from which wiring I68, suitably insulated, extends through thehousing I ID to a relay I62 controlling the elevator car control motorI54 connected to the electric line. The bridge I48 with its contacts I55and I52 and the points I54 and I56 constitute a switch I66 which, withthe switch I68 in series with the source of supply I6? and controlleddirectly by the operator, as by pushbutton, in an automatic elevator, orotherwise in a non-automatic elevator, controls the operation of themotor relay and hence themotor.

Mounted in suitable bearings in the housing III is a rock shaft I'II]having an outward extension to which is adjustably secured an arm I'I2carrying a cam roller I I4 adapted to cooperate with a stationary cam Ion the car if the car is not push-button controlled or with a retiringcam (not shown) with which the car, if pushbutton controlled, isequipped. Referring now more particularly to the latter type of car, itis well known that pushing any button closes a switch I68 and thisoperates a solenoid to retire the retiring cam, and if the car is putinto motion the cam will remain in a retired position. When the carnears the selected floor, the retiring cam will be automaticallyprojected toa position at which it operates to engage the roller I14 andswing the arm I72 to a more nearly vertical po- 'sition, thereby openingthe switch IE6 at the proper time to insure the cars coming to rest Theuse with its floor at the level of the sill 24. to which I put theretiring cam will appear presntly.

Fixed for rotation with the rock shaft I'iIl within the housing IIII isa locking arm I18 urged by a spring I in a direction to position the endI82 of the locking arm behind a locking lug I84 on the switch arm I'IB(Fig. 4), so as to obstruct movement of the switch arm toward the leftas shown in the drawings, 1.- e., toward openswitch position and preventunlatching of -the door, the locking arm I18 however being movable bythe-acticnof the retiring or other cam on the roller I14 against theresistance of said spring, to a position (Fig. 6) permitting open-switchmovement of the switch arm H8. I

Also mounted for rotation with the rock shaft I'IIJ is-a safety arm I85which may be employed in connection with a push-button controlled car,said arm I86 carrying a cam I88 of insulation material movable, by theaction of the retiring cam, between the contact bridge I48 and theadjacent stationary contact I54 to locksaid bridge in'open-switchposition, said safety arm being urged by the spring I89 towardinoperative position (Fig. 3), which it occupies upon retirement of theretiring cam. v

The housing I III has an opening I90 permitting the bolt I22 to beprojected partially out of the housing, the housing being provided witha suitable stop I92 e'ngageable with the lever "I I8, or other suitablemeans being provided, to limit the extent to which the bolt I22 may beprojected fromthe housing toward the door.

When the door is open, i. e., when the door panels 23 and-3i! aresubstantially apart, the latch bar I94 is entirely outside of thehousing III] as may be gathered from Fig. '7, an adjustable stop I94(Fig. 1) being provided to limit the extent towhich the latch bar I04may be projected by the V latch spring 92, I a

When the doorsections are latched togethe and the car has started on itstrip, the parts are disposed as shown in Figs. 1 to 4, wherein,referring particularly to Fig. 3, it will be noted that the switch I66is closed, the safety switch-opening cam I38 is in inoperative position,and the end I 82 of the locking arm I18 is disposed in obstructingrelation to the lug I84 on the lever H8, as shown in Fig. 4, making itimpossible for the latch bar IE4 to be retracted. Thus it is impossibleto accidentally open the switch I65 when the car is in motion and untilthe retiring cam on the car operates on the roller I'I4. When theretiring cam thereby separating the'contact I55 from the contact I54 soas to open the switch I66, bringing the car 32 to a stop with its floorflush with the sill 24. This rotation of the locking arm I13 causes theend I82 of said arm to be shifted to a position out of obstructingrelation to the lug I a l of the lever arm H3, as shown in Fig. 6.

Now the operator raises the'handle 88 (Fig. l), pulling the latch barN34 to the left from its Fig. position, the lug I84 moving past thelocking arm nd I52 to the extent permitted by the housing Illi, as atI92, until the interlock mechanism is arranged substantially as shown inFig. 7 (in which however the latch bar I04 is shown some what elevated,for a purpose which will appear). In this arrangement the contact I52has separated from the contact I56. Raising the handle 88 also moves thehook 98 laterally sufiiciently to enable it to passout of the openinghis of the lower door panel 35 as the door panels 28 and 3d areseparated. As the door panels are separated, the latch bar we passesupwardly out of the notch or socket I38 and clear of the housing 5 Iii.It will be noted that when the locking bolt I22 is withdrawn by thelatch bar I04 as just described, the projection I32 on said bolt isshifted to a position enabling the upper end 62 of the anchoring member56 to pass down clear of such projection, as is evident from Fig. 7, sothat the further upward and downward movements of the respective doorpanels 28 and 30 are unobstructed. The chain rod 64 is guided by a guideelement 696 suitably attached as at I98 to the housing I Iii.

The adjustable stop I 94 (Fig. 1) may be threaded in a bracket 2%mounted on the door panel 28 and serving as a guide for upward anddownward movement of a gravityor spring-actuated detent or keeper 202having a laterally projecting lug 2M adapted to be accommodated in anotch 29% in the latch bar I04. The keeper has its lower end 268extending through a guide opening 2H1 in the bottom I8 of the upper doorpanel 28 and adapted to rest on the top 89 of the lower door panel 38when the door is fully closed as shown in Fig. 1 and until the doors areseparated a slight amount, say about /8 inch. When the operator raisesthe handle 38, not only is the hook 93 shifted laterally to an extentpermitting it to pass through the opening I50 when the door panels areseparated, but the latch bar I M is moved to the left (Fig. 1) untilsaid bar is free of the housing IIU. At this time, the notch 206 in thelatch bar I64 is in a position to receive the" lug 204 of the keeper 2%upon slight separation of the door panels. When the operator raises thehandle 88 he not only moves the hook 98, latch bar HM and locking boltI22 to open the switch I85, but, as a part ofthe same operation, heraises the upper door panel 28 and thus, through the chain 58 and chainrod 64, enables the lower panel 30 to gravitate downward, whereupon thenotch 29% in the latch bar I04 receives the lug 204 on the keeper 292,and thus the latch bar I04 is retained in its retracted position untilthe door panels are again in such proximity that the top 30' of thelower panel 39 engages the bottom 2138 of the keeper 202 and lifts thelug 2M sufiiciently to separate the lu from the notch 206.

As the doorsproceed to separate, the latch bar lug I08 passes above thetop of the housing opening Hill, at which position the housing obstructssuch movement of the latch bar IM as would tend to return the lockingbolt I22 to switch-' closing position. When the separation of the doorsections has proceeded to such an extent that the latch bar lug I03 iscompletely free of the locking bolt I26, and until the separation of thedoor sections is complete, the projection I32 of the locking bolt I22 isinjuxtaposition to the served that the means just described for posi-LIO tively preventin closure of the switch independently of the wedgecam IE8 when the doors are not latched involves a substantialimprovement over the prior art, since it is dependent upon the parts 5%and 54, the removal of either or both of which would render inoperativethe suspension means whereby the doors are operated together. Thus myconstruction for preventing. closing of the switch IE6 while the door isopen is tamperproof.

When the door panels 28 and 3d are fully open, stop members 2 I2, ofwhich one is shown in Fig. 9, fastened to the top of the lower doorsection 38, engage the sill 24 with a trucking plate 2| 4 at the top ofsaid lower section substantially flush with said sill.

When it is desired to proceed with the car, the operator closes thedoor. As the upper door section 28 descends, the latch lug I63 ridesfree as indicated in dotted lines in Fig. '7, where it is held by thedetent 264, in position to descend into the notch I33 in the lockingbolt I22, entering said notch as the door panels come together. Thus thelatch bar lil l has no frictional contact with the housing I Hi or otherpart during the opening and closing of the door. Shortly before the dooris closed, the bottom 2% of the keeper 2%?2' engages the top 89 of thelower panel 36 and, as the panels thereafter approach closed positions,the keeper is raised, so that the keeper lug 20 i is freed of the notch2% in the latch bar IML. This occurs substantially when the upper end ofthe latch lug I68 has passed below the top of the opening I538 in thehousing Hill, the lug I238 being then disposed substantially entirely inthe looking bolt notch 53%, the hook 9% has passed below the lower panelflange 85], and the projection I532 on the locking bolt I22 has passedbelow the upper part 62 of the anchoring member 55. The compressionspring 92 then automatically moves the latch bar EM, the hook 558 andthe locking bolt I22 to the right as shown in the drawings. bringing theparts into the relation shown in Fig. 5. At such time the locking lug Hil of the switch lever I I8 is spaced from the adjacent wall 2I6 of thehousing sufliciently to permit the end I82 of the locking arm Ill! topass therebetw'een, and it will be noted further that while the contactsI52 and IE5 are allowed to engage, the Wedge cam I83 on the arm IE5 hasprevented the contact I56 from engaging the contact I54 with the resultthat the switch I65 is still open. The operator now pushes a car controlbutton (not shown). Pushing of the button closes the switch 58 (Fig. '7)and retires the retiring cam from the roller I14, enabling the spring Ito rotate the locking arm 57% until the end I82 of said arm is disposedbetween the lug IM of the switch lever I 18 and the adjacent housingwall M5, said spring thereby also rotating the rock. shaft lit! and withit the wedge cam arm 586, drawing the wedge cam I88 out of the way ofthe contact bridge Hi8, which is thereupon moved by the spring I46 in amanner to enable the contact I50 to engage the contact I54 and therebyclose the I switch I65 so as to operate the relay I62 and hence the carmotor I64 to move the car,

The safety wedge cam I88 is provided to satisfy UnderwritersLaboratories requirements for States requiringsuch a safety feature.However, this feature may be omitted as shown in Fig. 10, wherein(except for the cam I88) the construction and operation are identicalwith those hereinabove set forth.

In the event the arrangement of Fig. 10 is employed, the cam roller I14is moved by a stationary cam I'IS (Fig. 2) on the car every time theelevator car approaches a floor, thereby moving the locking arm I18 tothe position shown in Fig. 6. Thus the switch I66 cannot be openedunless the car is substantially at a floor. The switch IE6 is in serieswith a switch controlled by the operator, such as the switch I68 shownin Fig. 7, enabling him to bring the car to a stop at any floor withoutpreselecting the floor. If, after the locking arm I18 has been soshifted by the stationary cam on the car, the operator does not wish tostop the car at the adjacent floor, the stationary cam moves past theroller I'M, allowing the spring I80 to return the locking arm I18 to itsobstructing position as shown in Fig. 4, thereby positively preventingaccidental opening of the switch I66. If, at the time the locking armI78 is shifted to the position shown in Fig. 6, the car is brought to astop, then the operator can raise the handle 83 to thereby retract thelatch bar I534 sufficiently to withdraw the locking bolt I22 and therebyopen the switch I66. Thereafter the switch I55 can be closed onlyprovided the projection I32 on the locking bolt I22 is below the part 62of the anchoring member 56, and the latch bar lug I918 is below the topof the opening I99 in the housing I II at which time the door is closed.When the car is thereupon started, the stationary cam thereon movesbeyond the roller H4, allowing the spring I89 again to move the lockingarm III! to its Fig. 4 position preventing opening of the switch I66.

It will be apparent from the foregoing that I have provided afool-proof, simple and compact interlock which is entirely dependableand has allof the advantages herein set forth.

While there is shown and described herein certain specific structureembodying the invention, it will be manifest to those skilled in the artthat various modifications and rearrangements of the parts may be madewithout departing from the spirit and scope of the invention, and thatthe same is not limited to the particular forms herein disclosed, exceptinsofar as indicated by the appended claims.

I claim:

1 In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, means connecting said sections forsimultaneous movement, latch means including a movable latch member foreach door, a motor control switch associated with each door andincluding a switch arm movable into closed position by said latch memberwhen said latch member ismoved to latching position, and a motor controlcircuit including said switches, said motor being operative only whenboth switches are closed, and means for preventing closure of the secondswitch when said door, is open, said closurepreventing means beingprovided on said connecting means so as to be irremovabl e withoutrendering said connecting means inoperative.

2. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said 2 car, a motor control switch under the controlof the car operator, a biparting door comprising door sectionsassociated with each floor of said hoistway, means connecting saidsections for simultaneous movement, latch means including a movablelatch member for each door, a motor control switch associated with eachdoor and including a switch arm movable into closed position by saidlatch member when said latch member is moved to latching position, amotor control circuit including said switches, said motor beingoperative only when both switches are closed, means for preventingclosure of the second switch when said door is open, aidclosure-preventing means being provided on said connecting means so asto be irremovable without rendering said connecting means inoperative,and means for preventing opening of said second switch when said car isnot at a floor.

3. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said c r, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, means connecting said sections forsimultaneous movement, latch meansincluding a movable latch member foreach door, a motor control switch associated with each door andincluding a switch arm movable into closed position by said latch memberwhen said latch member is moved to latching position, a motor controlcircuit including said switches, said motor being operative only'whenboth switches are closed, means for preventing closure of the secondswitch when said door is open, said closure-preventing means beingprovided on said'connecting means I so as to be irremovable withoutrendering said connecting means inoperative, means for preventingopening of said second switch when said car is not at a floor, and meansincluding a cam on said car for rendering the second preventing meansinoperative when said car is at rest at a floor. r

4. In an elevator, a hoistway, a car in said hoistway, an electric motorfor said car, pushbutton control means for said motor, a door at eachfloor of said hoistway, a motor control switch comprising a movablecontact arm, a motor control circuit including said push-button controlmeans and switch, said motor being operative only when a push-buttonswitch and the other switch are both closed, a latch member for saiddoor and operative uponsaid switch arm to open and close said otherswitch, means movable with'said door and operative to prevent said armfrom closing said other switch when said door is open, and meanscontrolled by said car and preventing accidental closure of said otherswitch when'said car is substantially at rest at the selected floor.

5. In an elevator, a hoistway, a car in said hoistway, an electric motorfor said car, pushsaid door and operative upon said switch arm to.

open and close said other switch, means movable with said door andoperative to prevent said arm from closing said other switch when saiddoor is open, means controlled by said car and preventing accidentalclosure of said other switch when said car is substantially at rest atthe selected floor, and means controlled by said car for pre ventingswitch-opening movement of said switch arm when said car is notsubstantially at the selected floor.

6. In an elevator, a hoistway, a car in said hoistway, an electric motorfor said car, pushbutton control means for said motor, a door at eachfloor of said hoistway, a motor control switch comprising a movablecontact arm, a motor control circuit including said push-button controlmeans and switch, said motor being operative only when a push-buttonswitch and the other switch are both closed, a latch member for saiddoor and operative upon said switch arm to open and close said otherswitch, means movable with said door and operative to prevent said armfrom closing said other switch when said door is open, means controlledby said car and preventing accidental closure of said other switch whensaid car is substantially at rest at the selected floor, and meanscontrolled by said car for preventing switch-opening movement of saidswitch arm when said car is not substantially at the selected floor, thelast mentioned means being inoperative when said car is substantially atthe selected floor.

'7. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, one of said sections having a latchmember, a relatively stationary switch mounted in said hoistway inassociation with each floor and including a movable contact member, amotor control circuit including said switches, said motor beingoperative only when said switches are closed, and means connecting saiddoor sections for simultaneous movement, a connecting elementsubstantially rigid with one of said sections and forming an essentialpart of said connecting means, whereby removal of said element wouldrender said connecting means inoperative, said element having a recessdisposed to receive a part carried by said arm only when said door isclosed, to permit said arm to move into switch-closing position, aportion of said element adjacent said recess being disposed to obstructmovement of said arm into switch-closing position for all open positionsof said sections.

8. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, one of said sections having a latchmember, a relatively stationary switch mounted in said hoistway inassociation with each floor and including a movable contact member. amotor control circuit including said switches, said motor beingoperative only when said switches are closed, means connecting doorsections for simultaneous movement, a connecting element substantiallyrigid with one of said sections and forming an essential part of saidconnecting means, whereby removal of said element would render saidconnecting means inoperative, said element having a recess disposed toreceive a part carried by said arm only when said door is closed, topermit said arm to move into switchclosing position, a portion of saidelement adjacent said recess being disposed to obstruct movement of saidarm into switch-closing position for all open positions of saidsections, and means yieldably urging said contact am into switch-closingposition when said door is closed.

9. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting do'or comprising door sections associatedwith each floor of said hoistway, one of said sections having a latchmember, a relatively stationary switch mounted in said hoistway inassociation with each floor and including a movable contact member, amotor control circuit including said switches, said motor beingoperative only when said switches are closed, means connecting said doorsections for simultaneous movement, a connecting element substantiallyrigid with one of said sections and forming an essential part of saidconnecting means, whereby removal of said element would render saidconnecting means inoperative, said element having a recess disposed toreceive a part carried by said arm only when said door is closed,

to permit said arm to move into switch-closing position, a portion ofsaid element adjacent said recess being disposed to obstruct movement ofsaid arm into switch-closing position for all open positions of saidsections, and means including a latch member for moving said contact arminto and out of switch-closing position when said door is closed whilesaid car is substantially at rest at the floor associated with saiddoor.

10. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, one of said sections having a latchmember, a relatively stationary switchmounted in said hoistway inassociation with each floor and including a movable contact member, amotor control circuit including said switches, said motor beingoperative only when said switch-es are closed, means connectin said doorsections for simultaneous movement, a connecting element substantiallyrigid with one of said sections and forming an essential part of saidconnecting means, whereby removal of said element would render saidconnecting means inoperative, said element having a recess disposed toreceive a part carried by said arm only when said door is closed, topermit said arm to move into switch-closing position, a portion of saidelement adjacent said recess being disposed to obstruct movement of saidarm into switch-closing position for all open positions of saidsections, means including a latch member for moving said contact arminto and out of switch-closing position when said door is closed whilesaid car is substantially at rest at the floor associated with saiddoor, and means preventing unlatching movement of said latch member whensaid car is not substantially at rest.

11. In an elevator or the like, a hoistway, a car in said hoistway, anelectric motor for said car, a motor control switch under the control ofthe car operator, a biparting door comprising door sections associatedwith each floor of said hoistway, one of said sections having a latchmember, a relatively stationary switch mounted in said hoistway inassociation with each floor and including a movable contact member, amotor control circuit includin said switches, said motor being operativeonly when said switches are closed, means connecting said door sectionsfor simultaneous movement, a connecting element substantially rigid withone of said sections and forming an essential part of said connectingmeans, whereby removal of said element would render said connectingmeans inoperative, said element having a recess disposed to receive apart carried by said arm only when said door is closed, to permit saidarm. to move into switch-closing position, a portion of said elementadjacent said recess being disposed to obstruct movement of said arminto switch-closing position for all open positions of said sections,and means preventing switch-opening movement of said contact arm whensaid car is not substantially at rest.

12. In an elevator, a hoistway, a car in said hoistway, an electricmotor for said car, pushbutton control means for said motor, a door ateach floor ofsaid hoistway, a motor control switch comprising a movablecontact arm and a biased switch contact, a motor control circuitincluding said push-button control means and switch, said motor beingoperative only when a push-button switch and the other switch are bothclosed, a latch member for said door and operative upon said switch armto open andclose said other switch, means obstructing open-switchmovement of said contact arm while said car is en route to butsubstantially remote from the selected floor, and means controlled bysaid car and simultaneously opening said other switch and moving saidobstructing means to non-obstructing position when said carsubstantially reaches the selected floor, said controlled meansincluding a member forced by said car to move said contacttd open-switchposition in opposition to the bias thereon.

13. Inan elevator, a hoistway, a car in said hoistway, an electric motorfor said car, pushbutton control means for said motor, a door at eachfloor of said hoistway,a motor control switch comprising a movablecontact arm and a biased switch contact. a motor control circuitincluding said push-button means and switch, said motor being operativeonly when a push-buttonswitch and'the other switch are both closed, alatch member for said door and operative upon said switch arm to openand close said other switch, means obstructing open-switch movement ofsaid contact arm while said car is en route to but substantially remotefrom the selected floor, means controlled by said car and simultaneouslyopening said other switch and moving said obstructing means to nonobstructing position when said car substantially reaches theselectedfloor, said controlled means including a member forced by said car tomove said contact to open-switch position in opposition to the biasthereon, and means movable with said door to prevent said arm fromclosin said switch when said door is open.

14. In I an elevator installation including a hoistway having aplurality of landings with each of which the panels of a verticallysliding biparting hoistway door and switch are associated, a car havinga retiringcam and disposed in said hoistway, a motor for said car, apush-button control for said motor, a motor control circuit includingsaid switch. and push-button control,

,. said motor being operative only when said switch 12 for said door andconnected with said switch arm when said door is closed and beingmovable to latching position when said car is at rest at the associatedlanding, a member movably mounted at each landing and yieldably held ina position locking said switch arm in closed-switch position when saiddoor is latched, said member being movable from such position by theretiring cam to unlock said switch arm and against the resistance ofsaid spring to lock said bridge in openswitch position until said cam isretired while said switch arm is in closed-switch position, said latchbar being retractable, when said switch arm is unlocked, to unlatch saiddoor and move said switch arm to open-switch position, means formaintaining said latch bar inretracted position while said door is open,means connecting said door sections for simultaneous movement, and meansincluding said connecting means for looking said switch arm inopen-switch position while said door is open.

15. In an elevator installation including, a hoistway having a pluralityof landings with each of which the panels of a vertically slidingbiparting hoistway door and a switch are associated, a car having aretiring cam and disposed in said hoistway, a motor for said car, apush-button control for said motor, a motor control circuit includingsaid switch and push-button control, said motor being operative onlywhen said switch and a push-button switch are closed, the first switchhaving a movable arm and a springpressed contact, a latch bar for saiddoor and connected with said switch arm when said door is closed andbeing movable to latching position when said car is at rest at theassociated landing, a member movably mounted at each landing andyieldably held in a position locking said switch arm in closed-switchposition when said door is latched, said member being movable from suchposition by the retiring cam to unlock said switch arm and against theresistance of said spring to lock said contact in open-switch positionuntil said cam is retired while said switch arm is in closed-switchposition, said latch bar being retractable, when said switch arm isunlocked, to unlatch said door and move said switch arm to open-switchposition, means for maintaining said latch bar in retracted positionwhile said door is open, means connecting said door'sections forsimultaneous movement, and means including said connecting means forlocking said switch arm in open-switch position while said door is open.

16. In an elevator, a' hoistway, a car in said hoistway, an electricmotor for said car, pushbutton control means for said motor, a door ateach floor of said hoistway, a' motor control switch comprising amovable contact arm, a-

motor control circuit including said push-button control means andswitch, said motor being operative only when a push-button switch andthe other switch are both closed, a latch member for said door andoperative upon said switch arm to open and close said other switch,means movable with said door and operative to prevent said arm fromclosing said other switch when said door is open, means controlled bysaid car and preventing accidental closure of said other switch whensaid car is substantially at rest at the selected floor, and means formoving the last mentioned means to inoperative position before said carstarts.

EMORY W.. FENN.

